Checking FP4+ and PMK dev times...

[Tim V]

Hi guys,

I've been out and shot a bunch of FP4+ in 8x10" sheets and plan to use PMK to develop it. Just realised–being new to PMK–that at 20 degrees C., for 10mins mixed 1+2+100, the EI for the film is said to be 80-100ISO. I've shot at 125ISO, so any tips on where I should start time wise at 20 degrees C. at 1+2+100?

Help is much appreciated!

Thanks again,

Tim

[koraks]

I personally wouldn't bother about a difference between 100 and 125. 80 and 125 may start to rise beyond the variability due to inaccurate shutters and apertures. I think in your situation I would develop a sheet at 11 minutes just for peace of mind and evaluate the result, and then take it from there.

[esearing]

There is no right answer. Your process time for each sheet can vary depending on the scene SBR (3stops vs 8stops). Agitation can play a role too. Where you place your shadows and highlights may require you to expand or contract the development.

So you may start with a "Normal" or average development time, but if you take two exposures of the scene, you can alter the development of the second one based on the quality/outcome of the first one. Taking two or even three exposures while you are trying to nail down the perfect negative for your printing needs, will teach you what you need to do for each sheet. At some point you begin to think about the whole process while taking the shot.

Another way to determine if you like EI 80 vs 125 is to meter a distant scene for iso 125 on a sunny day. Select the F stop for the speed that gives you 1/125 (should be near f16) but set your shutter to 1/250th (assuming your shutter is accurate, if not adjust f-stop). Pull your darkslide half way out and fire it twice (2/250 = 1/125). Now pull the dark slide all the way out and fire another (1/2 negative is now 3/250 so near 1/80 or EI 80). Develop for your normal time. the 3/250 exposure should be slightly denser and give you an idea if you like the shadows better than the 2/250 exposure.

I personally always use EI 100 because I use both Delta 100 and FP4+ and have adjusted my development routine around that.

[Chuck Pere]

Another way to determine if you like EI 80 vs 125 is to meter a distant scene for iso 125 on a sunny day. Select the F stop for the speed that gives you 1/125 (should be near f16) but set your shutter to 1/250th (assuming your shutter is accurate, if not adjust f-stop). Pull your darkslide half way out and fire it twice (2/250 = 1/125). Now pull the dark slide all the way out and fire another (1/2 negative is now 3/250 so near 1/80 or EI 80). Develop for your normal time. the 3/250 exposure should be slightly denser and give you an idea if you like the shadows better than the 2/250 exposure.

.

Doing it this way wouldn't 1/2 be 1/250 exposure not 2/250? Or maybe my math is off this morning.

[esearing]

Doing it this way wouldn't 1/2 be 1/250 exposure not 2/250? Or maybe my math is off this morning.

"fire it twice" was the key statement for the first half then fire a third time for second half.

[Thalmees]

Considering the following sequence of EI: 64-80-100-125
Apparently, space of 1 EV, divided into thirds.
Assuming EI: 125 is adopted.
1. Two(2) exposures at 1/250 seconds, will hit the correct exposure at that IE: 125.
2. Three exposures of 1/250 seconds, will bring extra half(1/2) stop from the previous exposure, equivalent to the correct exposure of EI between 80 and 100(could be 90).
Mathematically, this exposure time(3/250 second) is equal to 1/83 second shutter speed.
3. Four(4) exposures of 1/250 seconds, will add a full stop to the first exposure(1), equivalent to the correct exposure of EI 64.
This calculation is not correct, if EIs 80 and 100, are not the correct "one third" stops between EI: 64 and 125.
Then, who care for 1/6th stop, between EI: 80 and EI: 90, in the real life of B&W photography?
True, it's too much near to EI: 80.

[bob carnie]

Hi guys,

I've been out and shot a bunch of FP4+ in 8x10" sheets and plan to use PMK to develop it. Just realised–being new to PMK–that at 20 degrees C., for 10mins mixed 1+2+100, the EI for the film is said to be 80-100ISO. I've shot at 125ISO, so any tips on where I should start time wise at 20 degrees C. at 1+2+100?

Help is much appreciated!

Thanks again,

Tim

I split into two 1 litre developer mix 7 min each for a total of 14 min... using jobo with medium to low rotation.

[Vaughn]

I split into two 1 litre developer mix 7 min each for a total of 14 min... using jobo with medium to low rotation.

Hi, Bob, is that to reduce the effect of the oxidation of the developer and/or to make sure you have enough developer per sq inch of film at your dilution?

Vaughn

[bob carnie]

Reduce the effect of oxidation as I use 2 - litre which is full tanks for each dev to make sure I have enough coverage.

[Tim V]

Thanks all.
I think I'll start with the first neg at 11min and see how it looks. I tend to be a little conservative with my metering, so will check the shadows are falling where I expected them to, then adjust accordingly, do another test, and so on. I'm new to PMK, so it's a hard one to judge the tanned negatives, but a quick proof print will do the trick.

Thanks again,

Tim